JPH0447896Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates as a whole to a low-pressure metal vapor discharge lamp with one, for example, bent discharge path.

[Conventional technology]

A low-pressure metal vapor discharge lamp, e.g. a fluorescent lamp, with a total of one e.g. bent discharge path,
Conventionally, as shown in FIGS. 5 and 6, a pair of straight tubes, each with one end closed, are spaced apart from each other and joined at the closed ends to form a single U. A phosphor coating 31 is formed on the inner surface of a glass bulb 30 forming a letter-shaped discharge path, and electrodes 32 are disposed at both ends of the discharge path.
It is formed by sealing mercury and a starting rare gas inside the 0.

It is conceivable that such a fluorescent lamp can be used as a surface light source, such as a backlight for a liquid crystal display, by taking advantage of the unique shape of the light source.

On the other hand, the mercury sealed in such a fluorescent lamp aggregates in the coldest part of the bulb as the lamp continues to be lit for a long time.

Normally, the tip connected to the end of the valve and sealed off after exhaustion is the coldest part, and mercury collects in this tip, but as shown in Figure 5, the tip is covered with a cap 33. In the case of such a structure, the chip part will not be the coldest part, and mercury will condense at the closed end of the arc tube.

[Problem that the invention attempts to solve]

Conventionally, as shown in FIG. 6, the cross-sectional shape of the tube constituting the valve 30 was a perfect circle, so the temperature distribution of the valve was relatively uniform in the circumferential direction, and as a result, the coldest part Although mercury is generated stably at a certain position called the closed end, it is not determined in which direction around the closed end it is generated. Therefore, when using a fluorescent lamp as a surface light source, mercury It may aggregate in a direction where it is noticeable.
In such a case, not only is the appearance unsightly, but visible light is absorbed, resulting in a decrease in luminous flux in a specific light irradiation direction, which is necessary as a surface light source.

These drawbacks were even more noticeable when the coldest part was formed on the wall of the valve pipe other than the closed end.

Therefore, the present invention provides a low-pressure metal vapor discharge lamp that forms the coldest part to make the part where mercury aggregates less noticeable, thereby improving the appearance and preventing a decrease in luminous flux in a specific irradiation direction. This is what I am trying to do.

[Means for solving problems]

The present invention provides a bulb in which a plurality of straight tubes are arranged at intervals from each other and the ends of these tubes are connected to each other to form a curved discharge path as a whole, and both ends of the discharge path are sealed. In the low pressure metal vapor discharge lamp, the tube has a flat cross section, and adjacent tubes are arranged in a plane along the long axis direction of the flat shape.

[Effect]

According to such a configuration, since the tube constituting the discharge path has a flat cross section, the end wall of the bulb wall in the long axis direction of the flat shape is closer to the wall in the direction perpendicular to the tube. The temperature is also low,
Moreover, since the adjacent tubes are arranged in a plane along the long axis direction of the flat shape, the end walls of the adjacent tubes facing in opposite directions, that is, the end walls located on the outside, become the coldest parts. Condensed mercury begins to collect on the outer end walls. This prevents the agglomerated mercury from adhering to the wall in the direction that is effective for irradiation, causing problems such as creating a shadow on the wall in the irradiation direction, making it unsightly, and reducing the luminous flux in that direction. It can be prevented. Moreover, since a gap is ensured between adjacent tubes, the temperature of the walls facing each other between adjacent tubes is prevented from increasing excessively.

[Example of idea]

The present invention will be explained below based on an embodiment shown in FIGS. 1 and 2.

In the figure, 1 is a glass bulb, and this glass bulb 1 has a pair of straight tubes 1a, 1a with one end closed, which are juxtaposed to form a gap between these straight tubes 1a, 1a. By electrically connecting the closed ends to each other, a generally U-shaped discharge path is formed as a whole.

A phosphor coating 2 is formed on the inner surface of the glass bulb 1, and electrodes 3 are provided at both ends of the discharge path. The inside of this valve 1 is filled with mercury and a starting rare gas.

Both ends of the glass bulb 1 are covered with caps 4.

Therefore, the straight tubes 1a, 1a are as follows:
As shown in FIG. 2, the cross section has a flat shape, and the adjacent straight tubes 1a, 1a are
They are arranged in a plane along the major axis direction XX of the flat cross-sectional shape, that is, in a horizontal row.

According to such a configuration, the temperature of the bulb during lamp lighting is determined by the temperature of the end wall a in the long axis direction is lower than the end wall b in the minor axis direction.

Moreover, since the adjacent straight tubes 1a, 1a are arranged horizontally in a row along the long axis direction XX of the flat cross-sectional shape, the adjacent ends of each straight tube 1a, 1a are than,
The temperature at the opposite end becomes lower.

Therefore, the coldest part occurs in parts a and a in FIG. 2, and mercury is stably aggregated in parts a and a during long-time lighting.

Moreover, this location is located in the long axis direction of the flat cross-section
- Since it is located at the end of Even if mercury aggregates, the appearance will not be impaired. In addition, even if the tube wall becomes black due to condensed mercury caused by long-term lighting in this area, it will not be noticeable as described above, so the appearance will not be impaired. Moreover, this effect becomes even more remarkable when the adjacent straight tubes 1a, 1a are arranged horizontally, that is, in a horizontal row, in the long axis direction XX with a flat cross section.

Furthermore, even if mercury aggregates in the a and a portions, the aggregated mercury is less likely to absorb light emitted in a direction opposite to the Z direction shown in FIG. That is, the second
The light output in the direction opposite to the Z direction in the light distribution characteristic A shown in the figure is that the straight tubes 1a, 1a are
In other words, since they are arranged horizontally in a row, even if light is absorbed by the aggregated mercury, the luminous flux in the opposite direction to the Z direction will not decrease much.

When used as a surface light source, as shown in FIG. 3, if a reflective film 10 is formed on one side of the flat cross-sectional shape divided along the long axis XX, the light emitted from the side used Strength increases.

In the above embodiments, the glass bulb 1 was constructed by connecting a pair of straight tubes 1a, 1a with one end closed and electrically connecting the closed end sides to each other. It is also possible to use a glass bulb 1 that has been bent into a U-shape in advance.

Further, the discharge path is not limited to a U-shape, but may be a W-shape or the like.

[Effect of idea]

As explained above, according to the present invention, since the tube constituting the discharge path has a flat cross section, the end wall of the bulb wall in the long axis direction of the flat shape is in a direction perpendicular to the tube. Since the adjacent tubes are arranged in a plane along the long axis direction of the flat shape, the outer end walls of the adjacent tubes facing in opposite directions become the coldest portions. As a result, mercury stably aggregates on the end wall of the flat shape in the long axis direction, and since this part is inconspicuous,
It is possible to prevent deterioration in appearance and also to prevent a decrease in luminous flux due to light absorption or light blocking effect of aggregated mercury.
Since a gap is ensured between adjacent tubes, the temperature of the walls facing each other between adjacent tubes is prevented from rising excessively.

[Brief explanation of drawings]

Figures 1 and 2 show an embodiment of the present invention, Figure 1 is a perspective view of a fluorescent lamp, Figure 2 is a sectional view taken along the line - - in Figure 1, and Figure 3 is a modification of the present invention. 4 is a perspective view showing another embodiment of the present invention, FIGS. 5 and 6 show conventional structures, FIG. 5 is a perspective view, and FIG. 6 is a perspective view showing another embodiment of the present invention. Medium-
It is a sectional view of a line. DESCRIPTION OF SYMBOLS 1... Glass bulb, 1a, 1a... Straight tube, 2... Fluorescent coating, 3... Electrode, 4...
...Base, 10...Reflection film.

Claims (1)

[Claims for Utility Model Registration] A bulb in which a plurality of straight tubes are arranged at intervals and the ends of these tubes are communicated to form a curved discharge path as a whole; A low-pressure metal vapor discharge lamp having electrodes sealed at both ends, characterized in that the tube has a flat cross section, and adjacent tubes are arranged in a plane along the long axis direction of the flat shape. A low-pressure metal vapor discharge lamp.